Small-molecule hsp90 inhibitors

A compound of the formula:

• wherein Y is C, N or O,
• R is hydrogen, a C1 to C10 alkyl, alkenyl, alkynyl, or an alkoxyalkyl group, optionally including heteroatoms such as N or O, or a targeting or labeling moiety connected to the left side adenine at N9,
• X4 is hydrogen or halogen, for example F or Cl, or Br;
• X3 is CH2, CF2, S, SO, SO2, O, NH, or NR2, wherein R2 is alkyl;
• and
• X2 is halogen, alkyl, alkoxy, halogenated alkoxy, hydroxyalkyl, pyrollyl, optionally substituted aryloxy, alkylamino, dialkylamino, carbamyl, amido, alkylamido dialkylamido, acylamino, alkylsulfonylamido, trihalomethoxy, trihalocarbon, thioalkyl, SO2-alkyl, COO-alkyl, NH2, OH, CN, SO2X5, NO2, NO, C═S R2, NSO2X5, C═OR2, where X5 is F, NH2, alkyl or H, and R2 is alkyl, NH2, NH-alkyl or O-alkyl;
• and
• X1 represents two substituents, which may be the same or different, disposed in the 4′ and 5′ positions on the aryl group, wherein X1 is selected from halogen, alkyl, alkoxy, halogenated alkoxy, hydroxyalkyl, pyrollyl, optionally substituted aryloxy, alkylamino, dialkylamino, carbamyl, amido, alkylamido dialkylamido, acylamino, alkylsulfonylamido, trihalomethoxy, trihalocarbon, thioalkyl, SO2-alkyl, COO-alkyl, NH2, OH, CN, SO2X5, NO2, NO, C═SR2 NSO2X5, C═OR2, where X5 is F, NH2, alkyl or H, and R2 is alkyl, NH2, NH-alkyl or O-alkyl, C1 to C6 alkyl or alkoxy;
• or wherein X1 has the formula —O—(CH2)n—O—, wherein n is an integer from 0 to 2, and one of the oxygens is bonded at the 5′-position and the other at the 4′-position of the aryl ring.